Typically when a person determines they need eyeglasses for vision correction, they go to an optician or optometrist who uses specialized equipment to determine the parameters required to ensure that the prescription and ophthalmic lenses are right for the person. Besides measuring the ophthalmic lens correction for the wearer, this typically includes measuring the pupillary distance, the fitting height or segment height, and possibly other parameters for individualized eyeglasses. This ensures that the frames and ophthalmic lenses are personalized and optimized for the wearer. Such specialized equipment, while producing very accurate measurements, is very costly, requires specialist training and knowledge, and typically takes up a lot of space within the optician's office. These measurements are used to either manufacture ophthalmic lenses (e.g., for prescription ophthalmic lenses such as progressives) and/or in properly centering and glazing ophthalmic lenses in frames (e.g., for stock ophthalmic lenses). Glazing is a term used to refer to the mounting or insertion of ophthalmic lenses in frames.
In recent years, companies have begun selling eyeglasses over the internet. There are typically two different systems for this. In a first system, described in U.S. Pat. No. 6,535,223, a person “virtually tries-on” eyeglasses by submitting a image of their face with a reference object on or near the face. The reference object is of a known size, and the image is scaled according to that. Virtual frames are placed over the image, and measurements such as pupillary distances can be calculated. However, such a system fails to take into account the differences in facial structure which cause frames to fit differently on different persons as well as the personal preference for where frames are worn on the nose (closer or further from the eyes). Thus, a virtual try-on method does not give accurate personalized measurements as to the person and the particular frame.
The second general method uses actual frames, and captures images and makes measurements, often using a known object for scaling, such as a coin or credit card held against the face in the captured image. One such system is shown in U.S. Pat. No. 9,091,867. This system allows a user to choose a frame, and then a calibrated frame which substantially matches the shape and size of the desired frame is provided. The user captures an image of the face with the frame on, and the calibration points on the frame are used to determine measurements for making the eyeglasses for the user, taking into account the preferred placement of the frame on the user. The ophthalmic lenses are glazed in the actual frame based on the measurements. However, these methods of measurement for online ordering are still not as accurate in capturing measurements as the methods typically used by opticians, and it can be costly to produce individual calibration frames for every frame design.